1. Field of the Invention
The invention generally relates to a sliding rail assembly for a sliding panel movable along a track. More specifically, the invention relates to using polymeric material to facilitate sliding movement of the panel along the track.
2. Description of the Related Art
Traditional assemblies for moving a panel include a surround which defines an opening and a pair of tracks which are disposed on opposite sides of the opening. The panel, such as a window or a door, is attached to the tracks and the panel is moved along the tracks to cover and uncover the opening. In these traditional assemblies, a guide ridge is typically formed along each of the tracks. Rollers are disposed on opposite sides of the panel for rolling the panel along the respective guide ridges. When the rollers are not in alignment with the guide ridges of the tracks, such as when the panel becomes warped or the tracks are out of alignment with respect to each other, which is a common result of poor installation or a subsequent accident dislodging the assembly, the assembly becomes difficult to move across the opening, i.e., binds, or the rollers become dislodged from the track.
Some assemblies have been developed to prevent the panel from binding or becoming dislodged from the tracks by incorporating a sliding rail assembly. An example of a sliding rail assembly which helps to prevent the panel from binding or becoming dislodged from the track is disclosed in U.S. Pat. No. 4,819,297 to Jacobs et al. (the '297 patent). The '297 patent discloses a surround defining an opening with a track disposed along a top of the opening. The track is formed from metal and includes a mounting plate with a runner having an L-shaped cross-section depending from the mounting plate. A glide is in sliding engagement with the track and attached to a top of the panel for supporting the panel while the glide and the panel slide along the runner of the track to cover and uncover the opening. The glide includes a finger and a hip spaced from the finger. The finger and the hip present a cross-section having an exterior surface and an interior surface disposed about the L-shaped cross-section of the rail for sliding engagement between the rail and the glide. The entire glide is formed from an injection molded plastic material. The glide is assembled to the track by fitting the hip over the L-shaped cross-section of the runner and rotating the glide about the runner and in sliding engagement. As the glide is rotated into place, the finger flexes, which allows the glide to surround and engage the runner. The plastic material will have the tendency to wear. This is because the plastic material of the glide slides along the metal track. Additionally, the hip supports the weight of the panel as the glide slides along the runner of the track. However, because the glide is formed entirely from the plastic material which is designed to flex, the glide limits the weight of the panel to which it may be attached in order for the track to support the load from the glide and the panel. Therefore, if a heavy panel is used, which would cause the glide to flex, a secondary track, which would include rollers along a bottom edge of the panel, must be incorporated to support the load of the panel while the glide and the runner act as only a guide at the top of the panel for guiding the panel across the opening.
Although the assembly described in the 297 patent eliminates the requirement of rollers on a track by using a glide sliding on the rail, there remains an opportunity for a sliding rail assembly which provides a rail and a glide which are capable of supporting heavy panels at only one end of the panel while still reducing the wear between the rail and the glide during sliding movement of the glide along the runner.